1. Field of the Invention:
The present invention relates to draglines and cable-supported cutting devices that can be supported by a cable with a dragline. Even more particularly, the present invention relates to an improved tree cutting device that can be suspended by a dragline lift cable and operated to traverse laterally and engage trees and the like for the purpose of lifting and/or cutting same.
2. General Background
In the clearing of right-of-ways for pipelines, roads and the like, it is common to use cutting devices with jaws which approach and shear the tree at its base. Many of these devices are mounted on backhoes, marsh buggies, swamp buggies and the like. Typically, such a gripping device requires a sophisticated heavy-duty apparatus costing hundreds of thousands of dollars, such as an amphibious backhoe or a backhoe on mats. Such a device typically manipulates the jaws to cut the trees with an extended linked hydraulically operated arm. This apparatus is highly specialized for the purpose of shearing trees and does an effective job. Examples of such devices include commercial units manufactured by Bucyrus Erie, Brott, Caterpillar, and the like. They are known as tree shearing devices, fellor-buncher and similar such terms.
The problem with these prior art devices is not that they are ineffective in shearing the trees and like obstacles. They are very expensive to operate and maintain.
There are a number of lesser expensive lifting devices which are used for a variety of tasks and are more of a multi-purpose type of heavy machinery. For example, a common dragline is simply a boom that is operated from a cabin. The cabin typically has an undercarriage of tracks and one or more winches wound with structurally sound wire rope. The rope is used to both raise and lower the boom as well as to lift cable which is wound upon the boom. Draglines commonly are used to lift heavy objects and to move these heavy objects to a desired location.
One of the most common methods of dredging a canal is to use a dragline and manipulate a relatively inexpensive bucket which can be, for example, a drag bucket or a clam bucket.
A number of devices have been patented which relate to the problem of cutting elongated devices such as trees, pile, and the like.
For example, the Corey U.S. Pat. No. 3,667,515, issued June 6, 1972, entitled "Pile Cutting Device," provides an apparatus that has a base with a guide adapted for receiving a pile, the base being adapted for reciprocal movement with respect to the pile, connectors affixed to the base for suspending the base in a substantially horizontal plane, a blade having a pair of opposite extremities, one of the extremities being pivotably mounted to the base, an actuator having a fixed member and a movable member, the fixed member being pivoted to the base and the movable member being pivotably mounted to the other extremity of the blade, the blade being swept across the guide when the actuator is engaged and being retracted away from the guide when the actuator is disengaged. When the pile cutter is lowered to the base of a pile, the guide being positioned about the pile for restricting the lateral movement of the base with respect to the pile, the actuator is engaged causing the blade to shear the pile at its base.
The Bannister U.S. Pat. No. 2,707,008, entitled "Tree-Handling Method And Airborne Apparatus," provides a gear-driven, cable operated device for cutting trees in remote locations.
The McRee U.S. Pat. No. 3,056,267, entitled "Method And Apparatus For Removing From Submerged Sites Portions Of Previously Driven Piles," discloses of a dragline operated device and a method for removing from submerged sites portions of piles previously driven at their lower end into the water bed and having cap ends exposed above the water line. A frame is used that can be laterally shifted to a position poised above the pile with an opening through the frame in alignment with the cap of the pile. The frame is then lowered, making the frame captive to the pile. The frame is then guided to the mud line and the pile is severed at the mud line.
A forest harvester is the subject of U.S. Pat. No. 3,638,693. The machine described in that patent is intended for separating standing trees. The apparatus is a wheeled A-frame type device that supports an open-ended gripping member.
The Choat U.S. Pat. No. Re. 31,481, entitled "Shear Type Tree Cutting Device," provides an apparatus with an elongated frame including tree clamping jaws supported at one end and a shear-type cutting blade supported from the frame for movement therealong between an inactive position remote from the jaws and an active position cooperative with the jaws to shear a tree member clampingly engaged by the jaws.
A grab-type tree harvester is the subject of U.S. Pat. No. 4,537,236, issued to S. Kulju. A pair of open-ended jaws is used to clamp the tree. A frame is connected to a lifting means through a rotating means in a manner such that the frame is adapted to rotate about a substantially vertical axis. The frame comprises grab means which are selectively moved by actuation means to an opened or closed position. Roller means for pulling a felled tree through the grab means is provided and at least one means for pruning a felled tree.
A hydraulically operated device for cutting trees, logs and the like is the subject of U.S. Pat. No. 3,270,787. That apparatus shows a hydraulic linked arm supported by a tractor with a pair of open-ended jaws at the distal end of the linkage.